using System.Collections.Generic;
using System.Drawing;
using System.IO;
using OfficeOpenXml;
using OfficeOpenXml.Style;

namespace WebInterface.Helpers
{
    /// <summary>
    /// Lot # / work order # template generator
    /// </summary>
    public class ExcelTemplateGenerator
    {
        /// <summary>
        /// Generates Excel spreadsheet data entry template
        /// </summary>
        /// <typeparam name="T">Data type of source data</typeparam>
        /// <param name="sourceData">Source data to display in template</param>
        /// <param name="headerText">Column header text</param>
        /// <returns>Generated spreadsheet</returns>
        public static byte[] Generate<T>(List<T> sourceData, string headerText)
        {
            //Create worksheet to hold data
            ExcelPackage package = new ExcelPackage();
            ExcelWorksheet worksheet = package.Workbook.Worksheets.Add("Data Entry Template");

            //Write header
            worksheet.Cells[1, 1].Value = headerText;
            worksheet.Cells[1, 1].Style.HorizontalAlignment = ExcelHorizontalAlignment.Center;
            worksheet.Cells[1, 1].Style.Font.Bold = true;
            worksheet.Cells[1, 1].Style.Fill.PatternType = ExcelFillStyle.Solid;
            worksheet.Cells[1, 1].Style.Fill.BackgroundColor.SetColor(Color.Gainsboro);
            worksheet.Column(1).Width = 45;

            //Write uploaded data
            if (sourceData != null)
            {
                int row = 2;
                foreach (T element in sourceData)
                {
                    worksheet.Cells[row++, 1].Value = element;
                }
            }

            //Write result
            MemoryStream fileStream = new MemoryStream();
            package.SaveAs(fileStream);
            fileStream.Position = 0;
            byte[] data = fileStream.ToArray();

            return data;
        }

        /// <summary>
        /// Generates Excel spreadsheet data entry template
        /// </summary>
        /// <param name="sourceData">Source data to display in template</param>
        /// <param name="headerText">Column header text</param>
        /// <returns>Generated spreadsheet</returns>
        public static byte[] Generate(object[][] sourceData, string[] headerText)
        {
            //Create worksheet to hold data
            ExcelPackage package = new ExcelPackage();
            ExcelWorksheet worksheet = package.Workbook.Worksheets.Add("Data Entry Template");

            int numColumns = headerText.Length;

            //Write header
            ExcelRange header = worksheet.Cells[1, 1, 1, numColumns];
            header.LoadFromArrays(new List<object[]> { headerText });

            header.Style.HorizontalAlignment = ExcelHorizontalAlignment.Center;
            header.Style.Font.Bold = true;
            header.Style.Fill.PatternType = ExcelFillStyle.Solid;
            header.Style.Fill.BackgroundColor.SetColor(Color.Gainsboro);

            //Write uploaded data
            if (sourceData != null && sourceData.Length > 0)
            {
                ExcelRange dataRange = worksheet.Cells[2, 1, sourceData.Length + 2, numColumns];
                dataRange.LoadFromArrays(sourceData);
            }

            //Size columns
            for (int col = 1; col <= numColumns; col++)
            {
                worksheet.Column(col).Width = 65;
                worksheet.Column(col).Style.Numberformat.Format = "@";
            }

            //Write result
            MemoryStream fileStream = new MemoryStream();
            package.SaveAs(fileStream);
            fileStream.Position = 0;
            byte[] data = fileStream.ToArray();

            return data;
        }
    }
}